Freightliner Argosy Evolution: Review

The bold exterior and interior features of the latest generation Freightliner Argosy Evolution Series are attributes that Daimler Truck and Bus Australia Pacific believe attract highly-skilled professional drivers to trucking fleets and increase payload capabilities for better revenues.

Some the of the exterior enhancements include a new distinctive-shaped grille, sun-visor with stainless steel insert, bright mirror head with stainless steel mirror arms, re-designed exterior oval grab handles and lower bumper valance panel.

However, the most notable change to the exterior is the uniquely-styled intake scoops on the front quarters. While the scoop on the driver’s side is purely for aesthetic balance, the scoop on the passenger’s side plays a major role in the engine cooling.

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That’s because it feeds ram air into a boxed channel funnelling airflow across the full-frontal area of a 500-square inch secondary radiator mounted under the rear of the passenger side cabin. The boxed channelling replaces the traditional mudguard and its underside is reinforced and further protected by dense spray matting.

The seat position is in alignment with the steering wheel and A-section dash and not compromised by an engine tunnel. Seats are positioned inward from the door allowing for plenty of shoulder and knee room for all sized drivers.

The steering wheel is adjusted by a foot operated control value safely tucked away beneath the dash. Both hands can remain on the wheel when adjusting the in-out or up-down position. An Airbag is also an option that is rarely available in a North American style truck.

Detroit's DD15

After a short stint behind the wheel of the new Argosy Evolution, which was powered by a DD15, it quickly became apparent that the new the cooling package certainly does its job well with fan on time hardly noticeable, and furthermore the intrusive noise of the fan greatly reduced compared to previous models.

According to Detroit’s literature the DD15 uses an advanced technology called Amplified Common Rail Fuel System, which means these engines optimise fuel economy and combustion. Meanwhile turbo compounding on the DD15 turns wasted exhaust gases into useable energy.

We’re also told that the DD15 features an extremely wide torque band, that lets it lug down to 1100rpm, which means less gear shifting for the driver.

The DD15 engine is a 14.8-litre, in-line-six with four valves per cylinder and two overhead camshafts. The backbone of this engine is the stiff cast iron alloy block that is designed to minimise engine noise and vibration. The gear train is rear mounted.

Meantime, the counter-weighted crankshaft is made of forged steel rotating in huge main and rod-bearing journals design to extend engine life and with increased engine loads.

Interestingly, the camshafts are hollow, unlike most engines that run solid camshafts, Detroit Diesel says this lowers the weight and inertia of the camshaft, improving throttle response. Each camshaft is dedicated: one for the intake valves, the other controls the exhaust valves and the integrated Jacobs engine brake.

Inside the DD15 there is a lot happening, however two particular features give the engine its personality and performance characteristics: The Amplified Common Rail System (ACRS) fuel injection system, and turbo-compounding.

ACRS develops injection pressures up to 32,000psi in a two-stage process. A gear-driven high-pressure fuel pump produces pressures in the common rail of 13,000psi, while the final pressure boost is achieved hydraulically within the injector itself. The system is capable of up to five injection events per cycle, optimising combustion efficiency while reducing engine noise dramatically.

All this enables better combustion management at any revs or engine load, and the next-generation DDEC VI electronic controller manages it all. Of course, injection pressures of that magnitude require extreme fuel filtration, so there's an easy-to-service two-stage fuel filter and water separator mounted on the left side of the engine. Both use cartridge filters, so replacement is accomplished without filter wrenches.

Then there are the turbochargers. There are indeed two of them, but they're not series-turbos as we are used to seeing on Caterpillar ACERT engines. The DD15 uses a simple primary turbo to boost manifold pressure for intake-air management. I say simple, because it's similar to the proven pre-1999 designs with none of the complex waste-gating or variable-geometry vanes we've seen on many engines in recent years.

The second turbocharger is the interesting one, in that it doesn't play much of a role at all in intake air management. Rather, it creates the manifold pressure differential required for exhaust gas re-circulation, and it pumps an extra 50 horsepower or so back into the engine’s rear drivetrain.

The combination of ACRS, turbo-compounding, and the rapid response of the primary turbocharger means that the DD15 exhibits up to 75 per cent better torque response than most other big-bore engines in the market today. What this means is it spools up very quickly to peak torque in 1.5 seconds as opposed to more than four seconds as is the case on many other engines so there is virtually zero turbo lag.

The additional insulation certainly works a treat with road noise hardly noticeable meanwhile ride and handling of the Argosy was first class.

Sadly, for Freightliner Argosy fans, this model will mark the end of an era for Freightliner’s iconic cabover model with production said to cease in 2020 ending a twenty-year run for the model.

Specifications:
Model: Freightliner Argosy (6x4)
Engine: Detroit DD15
Horsepower: 550hp (410kW) at 1850rpm
Torque: 1850lb/ft (2508Nm) at 1100rpm
Gearbox: Eaton Ultrashift
Fuel filter: Fuel Pro and fuel/water separator
Electrical: Leece-Neville 12V 185A alternator
Front axles: Meritor MFSß16
Front suspension: Taper leaf rated at 7,258kg
Rear axles: Meritor RT46-160 tandem drive
Rear axle ratio: 4.33
Rear suspension: Airliner tandem drive 46,000lb
Brakes: HD (P-type) drum brakes with auto slacks
Windscreen: Two-piece, flat
Interior: Cloth and studded vinyl upholstery package
Seats: Xtreme HD high back
Bumper: Polished alloy
Battery box: LHS under cab above tank
Extras: Bright finish bezel metric gauges